1. Field of the Invention
This invention generally relates to manipulating video content and more specifically to resizing video content.
2. Description of the Related Art
The sharing of video content on websites has developed into a worldwide phenomenon, supported by dozens of websites. On average, over 10,000 videos are posted every day, and this number is increasing as the tools and opportunities for capturing video become easier to use and more widespread. Millions of people watch the posted videos.
There is often a need to resize shared videos. For example, videos can be resized to aspect ratios compatible with various electronic devices, such as mobile phones. Videos can also be resized in order to allow for higher-quality transcoding for a given bit-budget. In addition, videos can be resized in order to support the extraction of representative thumbnail images or video segments.
One simple way to resize a video is to uniformly scale all of the content within it. This technique scales both salient and non-salient regions of the video and can have undesirable consequences. If, for example, the video includes an image of a face in a scene also having grass field, a uniform resizing can cause the resized image to be dominated by the grass field and make the face difficult to discern. In most situations, the face within the video would be considered the more salient region, and thus the uniform resizing emphasizes the non-salient regions at the expense of the salient region. Videos can also be resized by cropping out the non-salient regions. However, cropping is not effective unless the salient regions are spatially-close within the frames of the video.